Aryl borate compounds are a class of synthetic intermediates that are very important in the field of organic synthesis, so how to easily and efficiently synthesize various types of aryl boronate compounds has received continuous attention (see: Boronic Acids; Hall, DG; Wiley-VCH: Weinheim, Germany, 2005). The traditional method for synthesizing aryl borate is to react a halogenated aromatic hydrocarbon with a trialkyl borate under the action of a metal organic reagent such as an organozinc reagent, Grignard reagent, but there are many limitations for this method requires sensitive metal organic reagents (see: Suzuki, A.; Brown, HC Organic Syntheses via Boranes; Aldrich Chemical Co.: Milwaukee, 2003; Vol. 3). In order to avoid the use of the above-mentioned metal organic reagents, a cross-coupling reaction of a transition metal-catalyzed halogenated aromatic hydrocarbon and a boron reagent has been developed to synthesize an aryl boronic acid ester, and a palladium-based catalyst is used in a large amount (see: Ishiyama, T Murata, M.; Miyaura, N.; J. Org. Chem. 1995, 60, 7508); however, the use of palladium-based catalysts also has some disadvantages, most notably its expensive price.
Nickel based catalysts are very inexpensive compared to expensive palladium based catalysts and have significant cost advantages in industrial applications. Therefore, the development of nickel-based catalysts to achieve cross-coupling reaction of halogenated aromatic hydrocarbons with boron reagents to synthesize aryl boronic esters has received increasing attention. For example, a catalytic system consisting of 1,3-bis(diphenylphosphino)propyldichlorochloride and 1,3-bis(diphenyl-phosphino) propane can be used to achieve cross-coupling of brominated aromatic hydrocarbons and neopentyl glycol boron; catalytic system consisting of 1,3-bis(diphenylphosphino)propyldichloronickel and 1,1′-bis(diphenylphosphino) ferrocene, with zinc powder as an additive can efficiently catalyze the cross-coupling reaction of iodo-or-bromine aromatic with neopentyl glycol borane, which has better substrate suitability and higher catalytic efficiency. These results indicate that the relatively inexpensive nickel-based catalysts have great application prospects in the cross-coupling reaction of halogenated hydrocarbons with boron reagents for the synthesis of aryl boronate compounds, but these methods also have certain drawbacks, such as high reaction temperature of 100° C., and a catalyst amount of 10 mol %, and in particular, there is a problem that it cannot be widely applied to chlorinated aromatic hydrocarbon having a low activity but a relatively inexpensive and wide variety.
Cross-coupling reaction of chlorinated aromatic hydrocarbons and boronic acid pinacol ester can be obtained by using cesium fluoride as a alkali, trimethyl (2,2,2-trifluoroethoxy)silane as an additive and bis(trimethylphosphine)nickel dichloride as a catalyst, but the reaction temperature of the method still requires a high temperature of 100° C., and requires the use of more toxic trimethyl phosphine and more expensive additives. Using diisopropylethylamine as a base, the cross-coupling reaction of brominated aromatic hydrocarbons and chlorinated aromatic hydrocarbons with tetrahydroxydiboron to prepare aromatic boron acid can be carried out by using a catalytic system composed of 1,3-bis(diphenylphosphino)propyldichlorochloride and triphenylphosphine.